Automatic electric stapler



10, 1967 G. F. MANGANARO 3,346,163

AUTQMATI C ELECTRIC .STAPLER FIG.4

INVENTOR GEORGE. E MANGANARO 4s 44 BY ATTORNEY Oct. 10, 1967 Filed Oct.22, 1965 G. F. MANGANARO I 3,346,163

AUTOMATIC ELECTRIC STAPLER 2 Sheets-Sheet 2 FIG. 5

FIG. 6

INVENTOR GEORGE E MANGANARO ATTORNEY United States Patent 3,346,163AUTOMATIC ELECTRIC STAPLER George F. Manganaro, Cedar Grove, N.J.,assignor to Federal Tool Engineering Co., Cedar Grove, N.J., acorporation of New Jersey 7 Filed Oct. 22, 1965, Ser. No. 500,539 3Claims. (Cl. 227-131) ABSTRACT OF THE DISCLOSURE An automatic staplerhaving a solenoid-operated cam actuator for the movable stapler head anda simplified control circuit which renders the device substantiallyfoolproof by eliminating the possibility of false starts or prematurerecycling of the mechanism.

This invention relates to an automatic stapling machine.

The prime object of the invention is to provide a fully automatic lowprice stapler for home and ofiice use which is characterized bysimplicity of construction and operation, utilizing a minimum number ofmoving parts and requiring very little maintenance.

Another important object of the invention is to provide a simplifiedautomatic electric stapler including a novel control circuit whichrenders the operation of the device virtually fool-proof by eliminatingfalse or premature recycling of the mechanism.

Another object is to provide an automatic stapling machine which hasbuilt-in safeguards to prevent damaging of mechanical parts byoverloading caused by excessive work thickness or damaging of thesolenoid because of failure or improper functioning of other electricalcomponents. In accordance with the invention, the powering solenoid cannever at any time because of any component failure receive power for along enough period of time to damage it.

The above and other objects and advantages of the invention will bereadily apparent to those skilled in the art during the course of thefollowing detailed description.

In the accompanying drawings forming a part of this application and inwhich like numerals are employed to designate like parts throughout thesame,

FIGURE 1 is-a partly diagrammatic side elevation of an automatic staplerembodying the invention with the casing and base plate thereof shown insection;

FIGURE 2 is a fragmentary side elevational view of the stapler showingan adjustable sensing switch and associated parts;

FIGURE 3 is an end elevational view of the stapler with the casing andbase plate shown in transverse cross section;

FIGURE 4 is a schematic view of the stapler powering and controlcircuit;

FIGURE 5 is a side elevational view similar to FIG- URE 1 showing amodification of the stapler operating mechanism; and

FIGURE 6 is an end elevational view similar to FIG- URE 3 of thestructure in FIGURE 5.

In the drawings, wherein for the purpose of illustration are shownpreferred embodiments of the invention, the numeral designates aconventional office or home size paper stapler such as a type B8 Staplermanufactured by Bostitch, Inc., East Greenwich, R.I. The mechanicalconstruction and operation of the stapler is well-known and need not bedescribed in detail herein. Briefly, the stapler 10 embodies a head 11which swings vertically relative to an anvil plate 12 upon a pivot 13.Spring means 14 is provided within the stapler to return the staplerhead to the normal elevated position so that work may be introducedbetween the head and the anvil plate thereof.

The stapler 10 is suitably fixedly mounted upon a flat base plate 15which extends somewhat on opposite sides of the stapler mechanismproper, as shown in FIGURE 3.

A housing 16 of sheet metal or the like is provided for supporting andenclosing the various electrical and mechanical components of themachine and the housing is suitably detachably rigidly secured to thebase plate 15 so that it can be readily removed therefrom whennecessary. At its forward end and bottom, the housing has a relativelylarge horizontal entrance slot 17 for paper and other work to bestapled.

Mounted centrally within the housing and immediately above the stapleris a pusher type solenoid 18 having a horizontal reciprocatory armatureor core 19, held retracted by a return spring 20 whenever the solenoidis deenergized. The solenoid is pivotally suspended within the housingon a suitable pin 21 carried by a suspension bracket means 22. Thesolenoid carries and operates a cam or plunger actuator 23 at itsforward end having an inclined cam face 24, as shown, engageable with anactuator roller 25, mounted upon the top and forward end of the staplerhead 11. When the solenoid is energized, the cam 23 is thrust forwardlyto the broken line position of FIGURE 1 and the stapler head is forceddownwardly by the coaction of the cam face 24 and roller 25 to thestapling position. When the solenoid is de-energized, the cam 23 isretracted and the stapler head returns automatically to the normalelevated position.

Immediately above the forward lip 26 of cam 23 is a retainer or reactionroller 27 journaled upon a bracket 28, pivoted at 29 to a crosspinhaving its ends held in bearing brackets 30, FIGURE 3, secured to theside walls of the housing 16. A heavy compressible coil spring '31 bearsupon the tOp of the bracket 28 to force the retainer roller 27downwardly against the cam 23. The tension of the spring 31 may beadjusted by an adjusting screw 32 mounted upon the housing 16 as shown.By virtue of this arrangement, the work receiving gap of the staplermechanism may be adjusted, and jamming and possible damage to parts ofthe mechanism caused by excessive thickness of work is avoided. That isto say, the spring 31 will always yield somewhat if too great a load isplaced on the parts due to excessive thickness of the paper or work.

A main off and on switch 33 is suitably secured to the housing 16 nearits rear end, and a sensing microswitch 34 or the like is carried by abracket 35 which is adjustably secured to one housing side wall by meansof a clamping screw 36 which operates within a horizontal adjusting slot37 formed in the housing side Wall. The sensing switch 34 has an arm oractuator 38 directly in the path of the work which is introduced intothe stapling machine. By means of the arrangement shown, the position ofthe Work sensing arm 38 may be adjusted to various positions along theWork entry slot 17, see FIGURE 2.

Also mounted within the upper portion of the houisng 16 are a capacitor39, relay 40 and a rectifier 41, all conventional elements.

With reference to the circuit shown in FIGURE 4, a source 42 ofalternating current is connected by a wire 43 with the on and off switch33, in turn connected in series by a wire 44 with the center terminal 45of sensing switch 34 having a normally closed contact 46 and anothercontact 47. The contact 47 is connected with a wire 48 leading to oneterminal of solenoid 18, the other terminal of which is connected with awire 49 leading to a relay contact 50. The relay 40 has anotherstationary contact 51 and a movable contact 52 connected with a wire 53,in turn connected with a wire 54 extending back to the source of current42.

Another wire 55 leads from the sensing switch contact 46 to the currentrectifier 41, in turn connected with a wire 56, connected at 57 to therelay coil 46 which is also connected to the wire 54. Capacitor 39 isconnected across relay coil 40 by wires 58 and 59, connectedrespectively to wires 54 and 56, as shown. A potentiometer 60 may beincluded in the circuit as an optional feature to vary the resistanceacross the relay coil and hence lengthen or shorten the operating cycle.Increasing the resistance across the coil will lengthen the cycle, whilea decrease in resistance will shorten the cycle. The user of the deviceequipped with a potentiometer may vary the speed from severalmilli-seconds to several seconds, as found desirable.

The mode of operation of the automatic stapler is as follows:

The main switch 33 is activated to send current through the normallyclosed contacts of sensing switch 34 and through current rectifier 41 topower relay 46 with direct current. Consequently, relay 40 is alwaysenergized even when no paper is introduced into the slot 17 and whilethe stapler is not operating. At this time, the relay common contact 52leaves stationary contact 51 and engages contact 50 to close one leg ofpower to solenoid 18. However, solenoid 18 'will not operate untilsensing switch 34 is actuated due to contact of paper or other work withthe sensing or actuating arm 38 of switch 34. The capacitor 39 connectedacross the relay coil is also receiving charging current at this timewhile the main switch 33 is closed and while the stapler mechanism isstill idle.

The work to be stapled is now introduced into receiving slot 17 and thework engages sensing or actuator arm 38 and the common contact 45 ofswitch 34 is now shifted into engagement with contact 47. When thisoccurs, power to the relay coil 40 is interrupted. However, the relaycoil does not become de-energized immediately but is held powered by thecharge on capacitor 39 for an appreciable period of approximately 100milli-seconds in practice. The common contact 45 of sensing switch 34 inmoving to normally open contact 47 now energizes solenoid 18 through theclosed contacts 45 and 47 of the sensing switch and the closed contacts50 and 52 of the relay 40.

The charge on capacitor 39 now bleeds to a point below the operatingvoltage of relay 40 causing the relay to de-energize. When the relay 40is de-energized, contacts 50 and 52 are opened and solenoid 18 drops outor is de-energized, completing the stapling cycle. The solenoid remainsenergized until the charge on the capacitor 39 bleeds to the point wherethe relay 40 is de-energized.

This mode of operation provides a number of safety factors in thestapler. The solenoid 18 cannot remain on when the stapler is overloadedby work thickness beyond the capacity of the machine. If sensing switch34 fails in the actuated condition, solenoid 18 will operate and thende-energize and cannot remain on so as to cause improper recycling ofthe mechanism. If the relay 40 becomes faulty in the energized orde-energized conditions, the solenoid 18 will either operate one time ornot at all. Also, if the capacitor 39 becomes faulty, relay 40 will nothold, and as a result, the relay will not operate the solenoid underthese conditions. At no time through any component failure can thesolenoid, which is of the intermittent duty type, ever receive power fora long enough period to damage it. Furthermore, the invention circuiteliminates the need for any mechanical means to make and break thecircuit to the solenoid and insures against false recycling of thestapler. The circuit is completely automatic in operation. Selecting theproper value for the capacitor can either speed up or delay the cycle ofoperation, as desired.

In FIGURES and 6 of the drawings, there is shown a modification of thestapler operating mechanism. The

exact electrical circuit in FIGURE 4 is employed in this modification,without any change whatsoever, and the electrical mode of operation ofthe device is unchanged. It is simply the mechanical components inFIGURES 5 and 6 which have been modified to render the automatic staplerin this form somewhat more economical and more simplified.

In FIGURES 5 and 6, a housing 61 is employed including a base plate 62for the stapler 63 which is preferably the same Bostitch Stapler type B8employed in the prior form of the invention. In the present form, thestapler 63 does not have to be modified in any way and is installed onthe base plate 62 in the form in which it is furnished by themanufacturer. The stapler 63 includes a head 64 with contoured operatingpad or knob 65. The stapler head 64 swings upon a pivot 66 relative tothe stationary anvil 67.

The housing 61 supports and contains the same electrical controlelements utilized in the prior form of the invention, including the mainon and ofi? switch 33, sensing microswitch 34, capacitor 39, relay 46and rectifier 41. Additionally, the elements 35, 36, 37 and 38, allpreviously described in connection with the sensing switch, remainunchanged. The switch 34 is adjusted and utilized in the same manner inthe form of the invention shown in FIGURES 5 and 6.

A pull type solenoid 68 is supported within the housing 61 by suitablebracket means 69 and includes a reciprocable armature 70 having anaxially adjustable screw or stud '71 anchored to its forward end. Arigid stapler operating arm or lever 72 has its upper end hinged to thetop wall of the housing as at 73 and has a specially curved lowerextremity 74 which engages the pad 65 with a smooth cam-like action toassure steady and smooth operation of the stapler.

The lever 72 is linked to the stud 71 of the solenoid by means of aheavy pull spring 75, whose thickness is such that it will not deflector straighten under normal loading conditions. However, the spring 75will deflect slightly when the load is too great to avoid damaging anyof the parts and this is an important feature of the construction. Oneend portion 76 of spring 75 is apertured to receive the stud 71, and ashock-absorbing coil spring 77 surrounds the stud 71 and bears upon theend portion 76 to maintain the latter in contact with the stud head orlock nut 78, thereby eliminating chatter and lost motion. The other endof the spring 75 is apertured to receive a screw 79 or the like anchoredto the lever 72 near and above its lower end. Another shock-absorbingcoil spring 80 on the screw 79 bears against the adjacent end of spring75 to cushion the same. The shock-absorbing springs 77 and 80 allow freeaction of the leaf-type spring 75 during the full cycle of operation ofthe mechanism and no binding will occur. When the solenoid armature 70is completely home or retracted to actuate the stapler, the spring 75 isin substantially a true horizontal plane and this particular geometryeliminates wear and chatter in the solenoid. The spring 75 tends tobecome straight under load and, as stated previously, will yieldslightly when subjected to overload conditions.

The cycle of operation in connection with the circuit of FIGURE 4 isidentical in the construction of FIG- URES 5 and 6 and need not berepeated herein. All safety features and advantages present in theprevious form of the invention are still present in the embodiment ofFIG- URES 5 and 6 and the mechanical construction is even more simple.

When the solenoid 68 is energized, the armature 70 is retracted,resulting in the lever 72 swinging downwardly and forcing the staplerhead 64 down to the active position to staple the work. The parts returnautomatically to their inactive positions shown in FIGURE 5 uponcompletion of the cycle of operation. It is believed that the advantagesof the modified construction will be readily apparent to those skilledin the art.

It is to be understood that the forms of the invention herewith shownand described are to be taken as preferred examples of the same, andthat various changes in the shape, size and arrangement of parts may beresorted to Without departing from the spirit of the invention or scopeof the subjoined claims.

Having thus described my invention, I claim:

1. A stapler comprising a base plate including a stapler anvil, astapler head pivoted to the base plate and anvil and adapted to bedepressed for delivering staples to work resting on the anvil, anactuating roller mounted upon the stapler head near the forward endthereof, a reciprocatory cam above the stapler head having an inclinedcam face engaging the actuator roller shiftable in one direction todepress the stapler head and allowing elevation of the stapler head whenretracted in the opposite direction, automatic power means connectedwith said reciprocatory cam to operate the same for cycling the stapler,and adjustable yielding means arranged opposite the actuator roller andengaging said cam and permitting limited overload movement of the camlaterally due to excessive thickness of work introduced into thestapler.

2. The invention as defined by claim 1, and a housing for said stapler,and means forming a pivotal connection between said cam and cam powermeans and said housmg.

3. The invention as defined by claim 1, and wherein the adjustableyielding means comprises a spring, screwthreaded means to adjust thetension of the spring and a second roller urged by the spring intoengagement with the side of the cam remote from said actuator roller.

References Cited UNITED STATES PATENTS 1,940,980 12/ 1933 Svenson.

2,403,947 7/ 1946 Oussani 227131 X 2,770,805 11/1956 Elzer et a1.

2,910,700 11/ 1959 De Paolo.

3,058,117 10/ 1962 Moore 227-131 X 3,278,101 10/1966 Hatazaki 227-131 X3,282,489 11/1966 March 227131 X GRANVILLE Y. CUSTER, 111., PrimaryExaminer.

1. A STAPLER COMPRISING A BASE PLATE INCLUDING A STAPLER ANVIL, ASTAPLER HEAD PIVOTED TO THE BASE PLATE AND ANVIL AND ADAPTED TO BEDEPRESSED FOR DELIVERING STAPLES TO WORK RESTING ON THE ANVIL, ANACTUATING ROLLER MOUNTED UPON THE STAPLER HEAD NEAR THE FORWARD ENDTHEREOF, A RECIPROCATORY CAM ABOVE THE STAPLER HEAD HAVING AN INCLINEDCAM FACE ENGAGING THE ACTUATOR ROLLER SHIFTABLE IN ONE DIRECTION TODEPRESS THE STAPLER HEAD AND ALLOWING ELEVATION OF THE STAPLER HEAD WHENRETRACTED IN THE OPPOSITE DIRECTION, AUTOMATIC POWER MEANS CONNECTEDWITH SAID RECIPROCATORY CAM TO OPERATE THE SAME FOR CYCLING THE STAPLER,AND AD-